Method of forming reinforcing beads on conical paper cups



G. MERTA Feb. 10, 1942.

METHOD OF FORMING REINFORCING BEADS ON CONICAL PAPER CUPS 2 Sheeis-Sheet 1 Filed Feb. 23, 1940 Feb. 10, 1942. G. MERTA 2,272,920

METHOD OF FORMING REINFORCING BEADS ON CONICAL PAPER CUPS Filed Feb. 23, 1940 2 Sheets-Sheet 2 as gwwm 2 w &%Z

Patented Feb. 10, 1942 METHOD OF FORMING REINFORCING BEADS N CON'ICAL PAPER CUPS George Merta, Los Angeles, Calif., assignor to Paper Container Manufacturing Company, Chicago, 111., a corporation of Illinois Application February 23, 1940, Serial No. 320,408

7 Claims. (Cl. 93-36.5)

This invention relates to improvements in the method of forming reinforcing beads on conical paper cups, and the present application includes the improvements in bead forming disclosed in my application for Letters Patent filed October 7, 1938, Serial No. 233,890 and now formally abandoned.

One of the primary objectsof my invention is to provide a successful method of rolling a bead at the rim of a conical cup which has been previously formed from a paper blank in a manner well known to the art.

It is a well known fact that paper cups having no head at the rim are dangerous inasmuch as quite frequently people out their upper lips while drinking from such cups. Furthermore, considerable difiiculty is encountered in handling such a cup, particularly when filled with liquid. Because due to the flexibility of the cup the slightest pressure exerted in holding the cup tends to flatten it into an oval shape and thereby squeezing out and spilling the liquid. Also such cups present difliculty in dispensing due to the fact that the flexibility and the close nesting in a magazine stack make it difiicult to strip and withdraw individual cups from a dispensing device.

To overcome the above outlined objections to paper cups, a great deal of work has been done in developing processes for forming a bead at the rim of the cup, with considerable success on frusto-conical or fiat bottom cups, but heretofore with no success on the conical type of cup.

The first step in forming the bead in all of the successful processes is to press the conical wall of the cup to a substantially cylindrical form prior to rolling the bead. This is done very easily in the frusto-conical cups because the average included angle of the cone is about 14 degrees which requires very little pressure to form the cone into a cylinder and consequently the cup may be gripped at the fiat bottom without the danger of tearing the paper during this operation.

In the conical type of cup, however, to preserve good proportion, the included angle of the cone is usually approximately 40 degrees. This greatly increased angle presents a serious problem in forming the cylindrical portion prior to rolling the bead, due to the fact that greater pressure is required to form the cylindrical portion, and in addition the paper puckers up and becomes folded or pleated making it impossible to roll a uniform and compact bead. Therefore, heretofore all attempts at forming a bead on a conical cup have met with failure and the nearest thing to a bead that has been developed thus far is a partially rolled rim which does not reinforce the cup to any appreciable degree and still presents an edge on which the lower lip of the user may be cut.

In my method of head forming the entire cup surface not affected by the bead is securely gripped between conical male and female dies. The bottom of the portion to be formed into a cylinder is drawn out or expanded radially forming a slight step in the conical wall. The expanding of the paper at this point is controlled to decrease the angle about percent. Due to this decreased angle, the portion of the wall above the expansion point may be very readily formed into a cylinder. After the cylindrical portion is formed, it is rolled spirally into a compact bead by suitable dies.

Another object of my invention is to provide means for embossing a series of beads near the apex of the conical cup which serve to reinforce the cup at this point to prevent collapse when gripped to be withdrawn from a dispensing device. These embossed beads also provide. a rough surface which prevents the fingers from slipping thereby further facilitating the withdrawal of the cup from the dispensing device.

With these and other objects in view, the invention consists in the combination and correlation of forming reinforced beads on conical paper cups and which method will be described in the specification in detail and will be finally pointed out in the claims.

Referring to the drawings:

Figure 1 is a partially sectional view illustrating male and female dies with a conical cup therebetween and showing the external upper and lower dies for forming the rolled bead at the rim of the cup.

Figure 2 isa fragmentary enlargement of the left hand portion of Figure 1 to more clearly illustrate how a cup wall is expanded below the rim thereof.

Figure 3 is a view similar to Figure 2 but in which the lower ring die has been moved up .to form the portion of the cup wall above the expansion point into a cylinder. I

Figure 4 is a view similar to Figures 2 and 3 but showing the upper and lower ring dies moved down and showing in cross section the finished rolled bead at the rim of the cup.

Figure 5 is a fragmentary section of the upper portion of the cup wall illustrating the (litterence in angle between the upper portion after it has been expanded as shown in Figure 2 and the lower portion.

Figure 6 is a cross section through the male die illustrating the cup gripping means and the means for embossing a series of beads near the apex of the cup.

Figure 7 is a perspective view of the finished cup. 4

Reference I3 indicates a conical male die mounted on a mandrel II which in turn is associated with a suitable mechanism for intermittently revolving same and which does not form a part of this invention, therefore not shown in the drawings. The conical die III is provided with a gripper device I2 which includes a jaw I3 positioned at the apex of the die III. The jaw I3 is provided with a push rod I4 slidably mounted in bearings I5 and I6 in the body of the die III. The jaw I3 is normally urged into the closed position by means of a compression spring I! encircling the push rod I4 in an interposed relation between the end of bearing I5 and a washer I8 which in turn is retained by a pin I9.

The gripper jaw I3 is opened by means of a lever 20 pivoted in the body of die I as shown at 2I. The lever 20 is provided with a finger 2I which engages the bottom of a slot 22 in the push rod I4. The lever 20 is also provided with an extension 23 which is adapted to engage the end of a push rod 24 mounted within the mandrel II. It will be seen upon inspection of Figure 6 that the body of the die III is recessed to accommodate the operating mechanism for the gripper element I2. The push rod 24 is actuated to open and close the jaw I3 in a predetermined sequence by means of a suitable mechanism not illustrated.

The gripper element I2 is adapted to grip a small portion or tab of a paper blank used in forming the conical cup 25 around the die III. The blank may be of the character described in my copending application, Serial No. 183,143, filed January 3, 1938.

In the process of forming a bead at the rim of the cup 25, a female die 25 having a conical recess 21 is brought into engagement with the male die III, by suitable mechanism. not shown, to grip the tapered wall of cup 25 as shown in Figure 1. The male die I0 is provided with a shoulder 28 which cooperates with the edge 29 of the female die 25 to expand or stretch the wall of the cup at a point below the rim of the cup as best shown in Figures 1 and 2.

The stretching or expanding of the paper is controlled to reduce the angle of the upper portion 25a of the wall about 50 per cent as illustrated in Figure where it will be seen that if the angle of the conical wall of the cup is, for example, ,20 degrees the angle of the upper portion 25a of the wall may be degrees.

This reduced angle of the upper wall portion facilitates considerably the forming of said upper wall portion into a cylindrical section as shown in Figure 3.

The female die 28 carries on its outer diameter a sleeve die 33 which is moved upwardly by suitable mechanism not shown to form the upper portion 25a, in cooperation with the cylindrical portion 3I of the male die I0, into a cylindrical shape as illustrated in Figure 3.

The reduced angle of the wall portion 25a makes it possible to form it into a cylindrical shape by compressing the considerably reduced excess amount of paper without puckering or wrinkling and folding or pleating the paper as would be the case if the wall was not of a reduced angle. Also due to the reduced angle of the upper wall portion 250, the forming of the cylindrical portion may be done with less power.

After the cylindrical forming has been completed, a ring'die 32 slidably engaging the cylindrical portion 3| of the male die III is brought down to meet the sleeve die 30, as shown in Figure 3. The sleeve die 30 and the ring die 32 are provided with cooperating annular grooves 33 and 34 respectively.

The sleeve die 33 and ring die 32 are moved downward simultaneously to the position shown in Figure 4. During the downward movement of these dies the annular relatively sharp edge 35 of the ring die 32 engages the inner surface at the rim of the cylindrical wall portion 25a thereby causing said rim to expand outwardly and roll in a circular direction following the circumferential surface of the cooperating grooves 33 and 34 until the rim comes into contact with the cylindrical portion 25a where it is then rolled inwardly into a spiral forming a compact head 35, as shown in Figure 4.

From the foregoing description, it will be seen that the invention provides an efficient method for successfully rolling compact reinforcing beads at the rim of conoidal paper cups in which the wall is of a relatively great angle.

It is also desirable to provide reinforcing beads near the apex of the cup to facilitate the withdrawal of the cup from a nested stack in a dispensing device.

To provide the cup with the reinforcing beads near the apex, the female die 25 and sleeve die 30 are retracted from engagement with the cup 25. Embossing rollers 31 provided with flanges 38 and pivotally mounted in bearings 39 are brought into position by suitable mechanism not shown, so that the flanges 33 are in registration with grooves 40 in the die III and press the wall of the cup 25 into said grooves 40, then through rotation of die I0 and cup 25, a series of annular beads H are formed in the wall near the apex of the cup, as may be seen in Figures 6 and 7.

It will be noted that during the rotation of the die III, the cup 25 is still gripped in position by means of the gripper device I2 and to further prevent slippage of the cup on the die I0, an annular band of rubber or other friction producing material is inlaid into the conical face of the die as shown at 42.

After completion of the reinforcing beads, the cup is released and stripped from the die III by pushing the jaw I3 of the gripper device I2 outwardly from the die III by means of the mechanism described above.

Having thus described my invention I claim:

1. The method of forming beaded reinforcements on a conical paper cup, comprising gripping the cup between cooperating male and female dies, stretching the paper radially at a point below the rim of said cup to reduce the angle of the section above the stretching point, pressing said section above the stretching point into a cylindrical shape, rolling said cylindrical form spirally to said stretching point thus forming a compact bead at the rim of said cup, and rotating said cup and male die in cooperation with suitable means for embossing a series of reinforcing beads near the apex of said cup.

2. The method of forming bead reinforcements on conical cups, including gripping the cup wall between male and female dies, expanding the cup radially at a point below the rim of the cup to decrease the anglev of the wall between the rim and expanding point, forming the wall above the expanding point into a cylinder, rolling the cylindrical portion spirally from the rim to the expanded point to form a compact outwardly extending bead, and forming a series of annular grooves in the cup wall near the apex to reinforce the wall at this point.

3. The method of forming beaded reinforcements on conical cups, including radially expanding of the cup wall near the rim to decrease the angle of the wall portion between the rim and the expanding point, pressing the wall between the rim and expanding point into a cylindrical shape, rolling the cylindrical portion from the rim to the expanded point to form a compact bead, and embossing a series of annular beads adiacent the apex of said cup.

4. The method of forming bead reinforcement on conical paper cups, including expanding the cup wall outwardly at a point below the rim of said cup to decrease the angle of the wall portion between the rim and the expanded point, forming the portion between the rim of the expanded point into a cylinder, rolling said cylindrical portion into a bead, and embossing a series of annular beads near the apex of said cup.

5. The method of forming a head at the rim of a conical paper cup, including expanding the cup wall outwardly at a point below the rim of said cup to decrease the angle of the wall portion between the rim and the expanded point, forming the portion between the rim and expanded point into a cylinder, and rolling said cylindrical position into a bead, while supporting the cylindrical portion against inward deflection.

6. The method of forming a beaded rim on conical paper cups, including the gripping of a cup between cooperating male and female dies, stretching the cup wall outwardly at a point below the rim of said cup to decrease the angle of the wallposition between the rim and the stretching point to facilitate forming of said wall portion into a cylinder, forming the wall above the stretching point into a cylindrical shape, and rolling the cylindrical portion spirally outwardly from the rim to the stretched point to form a compactly beaded rim.

7. The method of forming beaded rims on conical paper cups, including radial expanding of the cup wall near the rim to decrease the angle of the wall portion between the rim and the expanding point, pressing the wall between the rim and the expanding point into a cylindrical shape, and rolling the cylindrical portion from the rim to the expanded point to form a compact bead.

GEORGE MERTA. 

